Process of preferentially modifying stereoregular polyhydrocarbons to improve dyeability



United States Patent 20 Claims ABSTRACT OF THE DISCLOSURE A process ofincreasing the aflinity of a stereoregular polyhydrocarbon for dyeswhereby a modifier is dispersed in the polyhydrocarbon predominantly inthe amorphous regions.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

This application is a joint continuation-in-part of my copendingapplications Ser. No. 400,611, filed Sept. 30, 1964, now Patent No.3,366,710, Jan. 30, 1968; Ser. No. 400,612, filed Sept. 30, 1964,abandoned; Ser. No. 406,- 631, filed Oct. 26, 1964, now Patent No.3,337,652, Aug. 22, 1967; Ser. No. 406,439, filed Oct. 27, 1964, nowPatent No. 3,375,213, Mar. 26, 1968; Ser. No. 414,919, filed Nov. 30,1964, now Patent No. 3,316,328, Apr. 25, 1967; Ser. No. 427,518, filedJan. 22, 1965, abandoned; Ser. No. 433,226, Feb. 16, 1965; Ser. No.491,055, Sept. 28, 1965, now Patent No. 3,337,651, Aug. 22, 1967.

It is generally recognized that dyeing takes place almost entirely inthe more open and more readily accessible non-crystalline or amorphousregions of a polymeric structure. When a modifier, which has been addedto the polyhydrocarbon to increase its aflinity for dyes, is entrappedin the crystalline portions of the molecule, it is not readily availablefor improvement in dyeability.

It is known that, in general, stereoregular polyhydrocarbons have ahydrophobic nature and it is difficult to disperse a hydrophilicmodifier therein to increase the aflinity of the polyhydrocarbon fordyes under normal processing conditions.

In the art, the conventional procedure for dispersing modifiers in thestereoregular polyhydrocarbon is to mix the modifier therein at atemperature of 50 C. to 150 C. above the melting point of thepolyhydrocarbon. The polyhydrocarbon does not exist in the crystallinestate at this temperature but rather is in a molten form. In this mannerthe modifier is dispersed throughout the mass. However, when the moltenmass is solidified, a crystalline area does form containing a majorportion of the entrapped modifier. As stated above, such entrappedportions of modifiers are unavailable for dyeing purposes. Also, thedispersion of the hydrophilic modifiers in the amorphous regions of thepolyhydrocarbon is poor due to the hydrophobic nature of thepolyhydrocarbon.

To overcome the above ditficulties inherent in the conventionalprocedure, it has been found necessary to utilize large portions of themodifier in order to entrap a satisfactory amount of the modifier in theamorphous regions of the polyhydrocarbon. It has also been foundnecessary to utilize high percentage of secondary dispersing aids forthe modifier above in order-to obtain acceptable results in dyeing.

. tile processing or product. It has also been found that a longretention time is required in commercially available equipment duringprocessing.

We have discovered a process wherein a hydrophilic modifier may beconcentrated in the amorphous regions of the stereoregularpolyhydrocarbon. This may be accomplished without the aid of secondarydispersing aids and with minor amounts of modifiers. It has been foundthat the dispersion of the modifier in the amorphous regions of thepolyhydrocarbon is accomplished with greater uniformity and a higherdegree of interaction between the dispersed modifier and thepolyhydrocarbon.

It is therefore an object of this invention to provide a process ofdispersing hydrophilic modifiers preferentially in the amorphous regionsof a stereoregular polyhydrocarbon.

Another object is to provide a process of increasing the dye afiinity ofstereoregular polyhydrocarbons with minimum amounts of hydrophilicmodifiers.

A further object is to provide a process of low cost, which is adaptablefor use under a wide variety of service conditions, whereby ahydrophilic modifier may be dispersed preferentially in a specifiedregion of a hydrophobic stereoregular polyhydrocarbon with ease andefficiency.

Other objects and many of the attendant advantages of this inventionwill be better understood by reference to the following detaileddescription.

The process of this invention, which accomplishes the preferentialdispersion of a hydrophilic modifier into the amorphous regions of ahydrophobic stereoregular polyhydrocarbon, in general, comprises themixing of a discontinuous physical mixture of the polyhydrocarbon andmodifier at a temperature between the first order transition temperatureand the second order transition temperature of the stereoregularpolyhydrocarbon at a pressure of to 20,000 pounds per square inch.

The first order transition temperature and the second order transitiontemperature are fully defined in Chapter 12 of Fibers From SyntheticPolymers, 1953, Elsevier Publishing Company and Chapter XXIII-3 inMan-Made Textile Encyclopedia, 1959, Interscience Publishers. Insummary, the first order transition temperature is the crystallinemelting point of the polyhydrocarbon and the second order transitiontemperature is the softening temperature of the non-crystalline portionsof the polyhydrocarbon.

In theory, at low temperatures, i.e. below the first order transitiontemperature of the polyhydrocarbon, the melt viscosity of thepolyhydrocarbon is very high permitting much higher shear stresses to betransmitted to the hydrophilic modifier. In addition, the mixingstresses are essentially localized in only the noncrystalline portion ofthe polyhydrocarbon thereby mixing the hydrophilic modifier therein.

The major problem with stereoregular polyhydrocarbon is to protect themagainst thermal and oxidative degradation during processing. If care isnot taken, the polyhydrocarbon will rapidly decompose and degrade to alow molecular Weight unstable product which is unsuitable for use inmaking shaped products. This is essentially the effect when a processingtemperature is utilized which is above the first order transitiontemperature of the polyhydrocarbon. Further, processing at suchtemperatures leads to the distribution of the modifier throughout themolten mass the major portion of which is crystalline in nature.Therefore a temperature should be used in processing which is below thefirst order transition temperature of the stereoregular polyhydrocarbon.

Also, when a temperature is used which is below the second ordertransition temperature, the non-crystalline or amorphous portion of thestereoregular polyhydrocarbon is in the brittle, non-plastic state and,as such, it will not mix and is otherwise unsuitable for processing.Therefore, the mixing stage should be above the second order transitiontemperature of the stereoregular polyhydrocarbon.

Further, the mixing stage should be carried out at a pressure between100 and 20,000 pounds per square inch. If a pressure is used which isbelow 100 pounds per square inch, there will not be a sufficientincrease in plasticity to permit acceptable mixing at temperatures belowthe first order transition temperature and an acceptable level of mixingis essential to uniform dispersion.

However, if the mixing stage of the process is in excess of 20,000pounds per square inch, the result will be mechanical degradation of thestereoregular polyolefin due to increased shear. It also results in areduction in production rate if not a shut down due to the inherentlimitations of the commercially available equipment.

Prior to the mixing stage of my process, the stereoregularpolyhydrocarbon and hydrophilic modifier may be prepared as adiscontinuous physical mixture in any manner known in the art.

However, it has been found that for greater ease of processing, thediscontinuous physical mixture of stereoregular polyhydrocarbon andhydrophyllic modifier should be heated to at least 50 below the firstorder transition temperature of the polyhydrocarbon prior to processing.The discontinuous mixture, which is not very plastic, is difficult tomix especially when there is very little pressure in the system. If themixture is heated to the temperature presented above, it becomessomewhat plastic for greater ease of processing in the mixing stage ofthe present process. In this manner processing is more effective andless time is required which is an economic advantage in commercialsystems.

It has also been found that if the discontinuous physical mixture issubjected to a pressure of 500 pounds per square inch, prior to themixing stage of the present process, much of the entrapped air isremoved from the mass and the mixture is more suitable for effectiveprocessing for it is more plastic and less time is required inprocessing to produce the results desired. If a pressure of 500 poundsper square inch is applied to the mass prior to processing, the pressureat the mixing stage should then be altered to between 500 and 10,000pounds per square inch. At 100 pounds per square inch pressure there ismarginal improvement in plasticity which is neces sary for effective andefficient mixing. If the pressure in the mixing stage of the process isincreased to at least 500 pounds per square inch, sufficient improvementin plasticity is achieved to render the processing more effective. As aresult, the modifier is more uniformly dispersed in the amorphousregions of the polyhydrocarbon and improvement in dyeability isachieved. Also, it is known that to process such a mixture withcommercially available equipment at reasonable rates, the pressureshould be below 10,000 pounds per square inch. However, with massiveequipment and lower production rates, the pressure may be increased to20,000 pounds per square inch.

After the hydrophilic modifier is dispersed in the amorphous region ofthe polyhydrocarbon in the mixing stage of the process, the mass may beformed by molding or die forming processes to the shape desired. Thisstep is carried out at a temperature of about 50 to 150 C. above thefirst order transition temperature for ease of forming. In this mannerthe viscosity of the material is lowered and the mass is made morefluid. This stage of the process should not be carried out above thetemperature prescribed because the material bing processed will degradeand discolor above this temperature and will be useless as a commercialproduct.

In theory, not all the crystalline matter goes into the molten statebecause of the limitation of time and temperature. In any case, it isbelieved that, due to the interaction of the modifier with the amorphousregions of the polyhydrocarbon, there is less tendency for the modifierto migrate to the crystalline portion even when the mass is renderedsomewhat fluid. Even if the crystalline portion of the polyhydrocarbonis rendered completely molten, there appears a preference for themodifier to remain associated with the less stereoregular portion of thepolyhydrocarbon which will again become the amorphous region when thematerial is solidified and crystallinity takes place.

After the material is formed, the shaped mass may be solidified simplyby contact with air, water or metal. This step is usually carried out atatmospheric pressure but not necesarily at a temperature below thesecond order transition temperature of the polyhydrocarbon.

To better explain my novel process, a brief discussion of the effects oftemperature and pressure on the plasticity and melt mixingcharacteristics of polymers, particularly as related to highlycrystalline stereoregular polyhydrocarbons, will be helpful. Pertinenttemperature limitations are best described in terms of the crystalline(first order transition) and non-crystalline or amorphous (second ordertransition) melting or freezing temperatures as determined underessentially normal ambient pressure.

As pressures are increased at temperatures below the crystalline meltingpoint, imperfect and smaller crystals begin to be disrupted and flow andincrease plasticity. At higher pressures with mechanical mixing andinternal working this increased plasticity and effective softening canbe accomplished at temperatures approaching the lower second ordertransition temperature. As an example, isotactic highly crystallinepolypropylene has a first order transition temperature or melting pointof about 170 C. at atmospheric pressure. Using the standard ASTM (MethodD 64856) heat distortion or plasticity test, isotactic polypropyleneunder a 66 psi. load softens and deforms at C. and under a 264 p.s.i.load softens at the low temperature of only 60 C. The limiting secondorder (non-crystalline freezing or thawing) temperature, below whichpressure fusion and melt mixing are impractical, is about -10 C. forisotactic polypropylene.

The above described effects of pressure on reducing the effectivetemperature at which the stereoregular polyhydrocarbon matrix in mydifferential mixing process will be sufficiently plastic to fuse andmelt mix, also have a similar effect on reducing the effective meltmixing temperature of the various hydrophilic polymeric modifiersdescribed in my copending applications. My hydrophilic polymericmodifiers are characterized by a higher dielectric constant and moistureregain than the polyhydrocarbon matrix, are soluble or dispersible inwater or oxygenated organic solvents (alcohols, ketones, ethers, etc.),are not soluble in the polyhydrocarbon, and are fusible at a temperaturenot exceeding the normal processing temperatures to 350 C.) of thepolyhydrocarbon. My water and oxygenated solvent compatible hydrophilicpolymeric modifiers are not soluble in, but can be fused and meltdispersed in the hydrocarbon polymer. If the modifier is too soluble inthe polyhydrocarbon it sweats out during processing, can be readilyremoved by water or solvent leaching and, in dyeing, gives excessivesurface dyeing and dye crocking and interferes with dye penetration. Inaddition, a soluble modifier, when melt mixed with a stereoregularpolyhydrocarbon and then solidified, remains in both crystallized andnon-crystalline or amorphous regains, will interfere with propercrystallization, and adversely effect stiffness and temperaturestability of fiber or film and will show negligible functional improvement.

My selected hydrophilic modifiers are fusible and dispersible in thepolyhydrocarbon but are not sufiiciently compatible to be a part of themore uniform and dense crystalline areas when they form duringsolidification. It appears that my modifiers not only concentrate in theamorphous areas during solidification but also form a continuous networkthroughout these areas and give maximum benefits in dyeability,particularly dye penetration.

I have now found, surprisingly, that further substantial improvements infunctional modification with my selected modifiers can be achievedduring initial modification of the polyhydrocarbon by melt mixing asdescribed, the modifier preferentially with the more amorphous portionsof the polyhydrocarbon while retaining the original better defined andlarger crystallites in a non-melted form. This is accomplished by mixingthe polyhydrocarbon and modifier under pressure at a temperature belowthe melting temperature of the more perfect crystallites but above thesecond order transition temperature (amorphous melting temperature) ofthe polyhydrocarbon.

This novel method of preferential melt modification of stereoregularpolyhydrocarbons with my selected hydrophilic polymeric modifiers has anumber of very desirable features. The modifieris initially concentratedin the amorphous regions where it is most desired in the final formedfiber or film. Well defined unmodified crystallites are retained anddeveloped to act as effective nucleation centers for improved crystaldevelopment and structural stability in the formed product. The meltviscosity and effectiveness of mixing at the lower temperatures are muchhigher than at the normally used temperatures well above the crystallinemelting point. Limiting the melt mixing to the amorphous polyhydrocarbonregions and the modifier reduces the proportion of total polymer beingworked, with a reduction in power requirement and more intensivedispersive action on the modifier. Eifectiveness of dispersion andretention of crystallites can be further improved by minimizing externalheating and relying on mechanical working under pressure to internallygenerate heat preferentially in the modifier and amorphous region. Theneed for the addition of expensive stabilizers to protect thepolyhydrocarbon during high temperature processing is reduced. Color ofthe modified polymer and uniformity of processing into fiber, film,coating or other structure are greatly improved. The amount of modifierand the need for lower melting secondary modifiers to improvedispersibility and dyeability in synergistic combinations with primarymodifiers are reduced. Numerous other advantages will be apparent tothose experienced in the art.

The benefits of my novel process may be accomplished in a practical wayby a combination of several process steps which may be carried outsequentially in continuous screw or impeller equipment or in batchmixers (Werner- Pfieiderer, Banbury, etc.) provided with suitable meansfor controlled heating, pressurizing, mixing, conveying and/or cooling,in direct combination or separately as required.

PROCESS As stated, I start with a discontinuous mechanical mixture ofpolyhydrocarbon and modifiers prepared by any of the methods known inthe art. The mixture, essentially free of moisture or solvents, is fedinto .a continuous screw or impeller extruder or a suitable batch mixerand subjected to heating at a temperature below the first ordertransition temperature or crystalline melting point and above the secondorder transition temperature or noncrystalline softening point of thepolyhydrocarbons (as determined .at atmospheric pressure) at initialpressures of less than 100 p.s.i. and with sufficient intensity ofmixing to compact the discontinuous mixture into a solid continuum, anda temperature below the normal melting temperature of thepolyhydrocarbon.

In the mixing stage of the process, the solid mixture of polyhydrocarbonand modifier at a pressure in the 6 range of 100 to 20,000 p.s.i.,preferably 500 to 10,000 p.s.i., is intensively mixed with little or noadded heat until the modifier is uniformly dispersed preferentially inthe amorphous portion of the polyhydrocarbon polymer and the modifiedpolymer is conveyed to the next step.

As an optional step, the modified polyhydrocarbon may then be heated fora short time up to or above the normal melting temperature of thepolyhydrocarbon, by continued mixing or by subsequent external heatingat high or reduced pressure, in order to facilitate manipulation intofiber, film, rod and tubing.

In the last stage of the process the formed structure is solidified bycontact with a solid, liquid or gas at a reduced pressure andtemperature.

These steps may be carried out sequentially or intermittently with theaddition of other steps as required.

As a preliminary step, I prefer to initiate my process by heating thepolymer-modifier mixture to a temperature at least 25 C. and preferablyat least 50 C. below the crystalline melting temperature of thestereoregular polyhydrocarbon. Conveniently, the polyhydrocarbon andmodifier may be pre-mixed in powder form or the modifier in solution maybe coated on the polyhydrocarbon, in powder or pellet form and thendried prior to the actual mixing stage of the process. The temperatureshould be sufficiently low to permit higher pressure melt mixing in themixing stage without excessive temperature buildup.

The mixture may be slightly heated and/or cooled in the mixing stage tomaintain the desired intermediate temperature for optimum uniformpreferential mixing with good production rate. Heating and/or coolingmay be accomplished by circulation of temperature controlled water, oilor other liquid through external jacket, extruder screw, impeller,mixing arm, etc.

In the forming stage, where a temperature above the crystalline meltingpoint may be required, pressure, time and intensity of mixing should beminimized for maximum retention of crystallites. Crystallite retention,however, is not a requirement of my process as long as the initialmodification was carried out under suitable conditions for mypreferential melt mixing process. Under optimum conditions, incontinuous processing, all process steps may be accomplished in two tofifteen minutes process or retention time. Similar batch processingusing, for example, a combination of a Banbury mixer and a two rollsheeting mill may require from ten to thirty minutes. A minimum of abouttwo minutes overall process time appears to be necessary to obtainuniform results. Processing requiring more than thirty minutes mayresult in excessive mechanical degradation, increased color andexcessive equipment and power costs.

The following examples illustrate but are not intended to limit my novelmethod for preferential modification of stereoregular polyhydrocarbons.

Example 1 Ninety-five parts by weight of finely powdered (50 to 200mesh) isotactic poly-4-methyl-1-pentene (M.P. about 235 C., isotacticityabout was intimately tumble mixed with five parts by weight of finelypowdered (50 to 200 mesh) poly-N-vinyl-methyloxazolidinone (M.P. about250 0., molecular weight about 150,000).

The powder mixture was then fed into the hopper of a sturdy 2.5 inchdiameter, 30:1 L/D ratio continuous screw compounding extruder having aconventional polyethylene type screw, five throttling type temperaturecontrolled barrel zones, a back pressure regulating gate valve and aheated strand, die with eight /8 inch holes. The L/D ratio refers to theeffective length to diameter ratio of the extruder screw in the barrel.The throttling or compensating type temperature controls supplement theheat generated by melt mixing with the minimum supplemental heating orcooling required to maintain the preset zone barrel temperature. A verysturdy extruder was used with a drive and gate valve capable ofdeveloping a 20,000 p.s.i. back pressure. The extruder was set up insuch a way that the extruded strands were cooled in a water bath andthen cut into small pellets as is normal in the art.

The extrusion mixing was performed under two sets of conditions. In the1A or blank test, compounding was carried out under normal conditionswith the barrel zone temperatures of 250-250-250-250275 C., a backpressure of 450 p.s.i., and a die temperature of 300 C. The extrudrerscrew was driven at maximum speed and the polymer retention time wasabout 4 minutes. The strands were cooled, pelletized, dried, storedunder dry conditions and labeled Test 1A.

Test 1B was run in similar fashion except that the barrel zonetemperatures were set at 150l75175200-245 C., the gate valve wasadjusted to give a back pressure of 20,000 p.s.i. and the dietemperature was set to maintain a die temperature of 265 C. In the firstor back zone the powder mixture was compacted to remove air and waspreheated at a temperature well below the first order transitiontemperature of the stereoregular polyhydrocarbon, in zones two to fourthe mixture was intensively mixed while still at a temperature below thecrystalline melting temperature to uniformly disperse the modifierpolymer preferentially throughout the amorphous portion of thepolyhydrocarbon while under a very high backpressure, in zone five thetemperature was increased to slightly above the crystalline meltingtemperature, and, after passing the processability. Similar results wereobtained using isotactic polystyrene instead of thepoly-4-methyl-l-pentene.

Example 2 In accordance with the procedure of Example 1, I prepared andevaluated modifications of a representative stereoregular polypropylene(M.W. about 350,000, M.P. 170 C., melt index 3, and isotacticity of 95%)using normal (200200-200200250 C. zone temperatures, 400 p.s.i.backpressure and 250 C. die temperature) and my preferential(ll20135-150-170 C. zone temperatures, 8000 p.s.i. backpressure and 200C. die temperature) compounding conditions.

The modifications A to H were made at the by weight level using highmelting primary polymeric modifiers (4% by weight) in synergisticcombination with lower melting polar compounds or selected secondarypolymeric modifiers (1% by weight). Modifications A and B were made withprimary modifier carboxymethyl cellulose (1.3 substitution, mediumviscosity) and tertiary dihydrogenated tallow methyl amine, C and D weremade with primary modifier sodium salt of sulfonated polyvinyltoluene(M.W. 400,000) and quaternary dihydrogenated tallow dimethyl aminechloride, E and F were made with primary modifierpoly-N-vinyl-methyloxazolidinone and polyvinyl methyl ether (M.W.10,000), G and H were made with primary modifier poly-N-vinylpyrrolidone (M.W. 40,000) and a polycondensate of adipic acid andpropylene glycol (M.W. 12,000).

Results of the dispersion uniformity tests were as follows:

Normal process. Preferential process Spin draw, r.p.m holes plugged,minutes Holes plugged, 4 hours None None None None gate valve, thepolymer was further heated at a reduced pressure for a short time tofacilitate proper strand and pellet formation. The total retention timewas about 7 minutes and the modifier was preferentially mixed with theamorphous portion of the polyhydrocarbon under high pressure for morethan 3 minutes. Similar tests were repeated using only 2% modifier withnormal processing (1C) and my preferential processing (1D) conditions.

In order to compare the uniformity of dispersion of the modifier in thetests they were run individually through a normal single endmultifilament extruder-gear pump-die combination and down through an airquench pipe to cool the extruded fibers. The fibers were extruded at 310C. through a die with 30 holes having 0.025 inch diameters. Uniformitywas compared two ways. First, the spin draw limit of the extrudedmultifilament yarn was determined by winding the yarn on variable speedtake-up tube and gradually increasing the take-up speed (r.p.m.) untilthe filaments began to break. In the second uniformity test,multifilament extrusion continued for four hours or until at least 10%(3 holes) in the die became plugged. The following results wereobtained:

Test 1A Test 10 Test 1B Test 1D Uniformity of dispersion of themodifiers was greatly improved using my preferential modificationprocess.

Example 3 In accordance with the procedure of Example 1 and theprocessing temperatures of Example 2, I prepared and evaluated modifiedstereoregular polypropylene (film grade, melt index 15, M.P. 170 C., andisotacticity 99% The back pressure for the normal processing was 200p.s.i. and for my preferential processing was 500 p.s.i. The polymerretention time in the preferential compounding was down to about 3minutes overall and between 1 and 2 minutes under pressure at atemperature below the crystalline melting temperature.

The modifications were made with representative hydrophilic heterocycliccopolymers at 10 to 15% by Weight levels. Modifications A and B weremade with a 50/ 50% by weight copolymer of N-vinyl-methyloxazolidinoneand vinyl acetate at a 15% level, C and D were made with a /30 copolymerof N-vinyl pyrrolidone and ethyl acrylate at a 15 level, E and F weremade with a partially substituted or grafted poly N-vinyl pyrrolidonehaving /20 N-vinyl pyrrolidone and N- Emir-211W 1i mir,r .r 4 5 0002,000 2,800 65 vinyl lauryl-pyrrolidone at a 10% level, and G and Hoespugge ,mms... 60 i f plugged Moms 1) 0) f made Wlth a 60/40 copolymerof N vinyl morpholme and methyl methacrylate at a 15% level. None. Theevaluation results were as follows:

A B C D E F G H Normal process X Preferential process X n X X Spin draw,r.p.n1 10% holes plugged, minut Holes plugged 4 hours One Thepreferentially modified polyhydrocarbons in the X X X X 6 Two None Evenat high levels of modification my preferential greatly improvesuniformity of dispersion.

9 Example 4 In accordance with the compounding procedures of Example 1,I prepared modifications of a representative linear polyethylene(density 0.95, M.P. 135 C., molecular weight about 100,000) using normal(160-160-160- 170-180 zone temperatures, 250 p.s.i. back pressure, and210 C. die temperature) and my preferential (80-100- 110-125-145 C. zonetemperatures, 1000 p.s.i. back pressure, and 165 C. die temperature).

Modifications were made at the 10% by weight level using a 50/50% byweight copolymer of ethylene and maleic anhydride (A and B), polyvinylmethyl ether (C and D) and a 60/40% by weight copolymer of vinyl methylether and maleic anhydride.

To compare uniformity of dispersion, the modified polyethylene pelletswere oven dried and then extruded under normal conditions into blownfilm using a one inch 12:1 L/D laboratory extruded and a crosshead die(tip 0.638" OD. and orifice 0.681" I.D.). The films, processed undersimilar conditions, were then compared subjectively for uniformity ofappearance. The modifications prepared under normal compoundingconditions did not blow up or draw uniformly and gave uneven, streakyfilms. Similar modifications prepared under my preferential processingconditions, blew up uniformly and gave even films with no streaks.

Example In accordance with the procedure of Example 1 and the processingtemperatures of Example 2, I prepared and evaluated modifiedstereoregular polypropylene (film grade, melt index 15, M.P. 170 C. andisotacticity 99%). The back pressure for the normal processing was 200psi and for my preferential processing was 500 psi. The polymerretention time in the preferential compounding was down to about 3minutes overall and between 1 and 2 minutes under pressure at atemperature below the crystalline melting temperature.

The modifications A to H were made with representative primaryhydrophilic copolymer modifiers with and without low percentages ofsynergistic secondary modifiers using normal and preferential processingconditions. Modifications A and B were made with a 50/ 50% by weightcopolymer of N-vinyl methyloxazolidinone and vinyl acetate at a byweight level, modifications C and D were made with 9.9% of the previouscopolymer together with 0.1% of a polycondensate of dimerized linoleicacid and triethylene tetramine (M.W. 6000, amine value of 90),modifications E and F were made with 10% by weight of a 70/ 30% byweight copolymer of N-vinylpyrrolidone and ethyl acrylate andmodifications G and H were made with 9.8% of the previous copolymertogether with 0.2% by weight of oleylamide.

The evaluation results were as follows;

l T.1. Transition temperature.

Without adversely affecting the crystalline melting point ofstereoregular hydrocarbons, they can be copolymerized with minorpercentages of other monomers to greatly reduce the second ordertransition temperature or brittle point and increase the temperaturerange effective under my novel preferential melt dispersing process. Forfiber use it is preferred that the major monomer in the stereoregularpolyhydrocarbon constitute at least 85% by weight of the polymer andthat the melting temperature of the hydrocarbon polymer or copolymer beat least 150 C. For use in coating or adhesive bonding applications thecomonomer may constitute up to 49% by weight of the polymer and themelting temperature may be as low as 100 C. The comonomer used may beone or more of the other monomers used in making the listed homopolymersor they may be any other substantially hydrocarbon monomer which doesnot significantly change the hydrophobic or the stereoregular characterof the polymer. The comonomer may be present sequentially in the polymerin an individual comonomer or a prepolymer block form in relation to theprincipal hydrocarbon monomer in the polymer.

Obviously, many modifications and variations of the present inventionwill become apparent to one skilled in the art in view of the aboveteachings. For instance, functional improvements such as adhesion,printability, and static resistance are also strongly dependent on thepref erential modification of the amorphous regions. It is therefore tobe understood that the invention as set forth in the appended claims maybe practiced otherwise than as described.

I claim:

1. A process of dispersing dye affinity improving hydrophilic modifierspreferentially into the amorphous regions of a stereoregularpolyhydrocarbon comprising:

providing a compacted discontinuous physical mixture of 80 to 99% of astereoregular polyhydrocarbon and 1 to 20% of a hydrophilic modifier,and

mixing said discontinuous physical mixture into a continuous mass at atemperature between the 1st order transition temperature and the 2ndorder transition temperature of said stereoregular polyhydrocarbon at apressure of 100 to 20,000 pounds per square inch.

2. The process of claim 1 wherein the 1st order transition temperaturelies in the range of 100 C. to 350 C. and the second order transitiontemperature lies in the range of 25 C. to 100 C.

3. The process of claim 1 wherein said stereoregular polyhydrocarbon ispolyethylene and said mixing stage Normal process. Preferential process-Spin draw, rpm..- 10% holes plugged, minutes Holes plugged 4 hours One.iiii''. n One X X X X 00 1, 300 450 1, 800 400 1,400 550 2, 000 40 5550 Even at high levels of modification my preferential process greatlyimproves uniformity of dispersion.

The following are included in the list of stereoregular polyhydrocarbonswhich may be processed to increase their affinity for dyes with their1st order and 2nd order transition temperatures set forth.

5. The process of claim 1 wherein said stereoregular polyhydrocarbon ispoly-4-methyl-1-pentene and said mixing stage is carried out at atemperature between C. and 235 C.

6. The process of claim 1 wherein said stereoregular polyhydrocarbon ispolystyrene and said mixing stage is carried out at a temperaturebetween 100 C. and 230 C.

7. The process of claim 1 wherein said stereoregular polyhydrocarbon isisotactic poly-l-butene and said mixing stage is carried out at atemperature between C. and 127 C.

8. The process of claim 1 wherein said stereoregular polyhydrocarbon ispoly-3-methyl-l-butene and said mixing stage is carried out at atemperature between 50 C. and 310 C.

9. The process of claim 1 wherein the physical mixture of stereoregularpolyhydrocarbon and hydrophilic modifier is heated to a temperature ofat least 50 C. below the 1st order transition temperature prior tomixing.

10. The process of claim 9 wherein said heating is carried out at apressure of less than 500 pounds per square inch and said mixing iscarried out at a pressure of 500 to 10,000 pounds per square inch.

11. The process of claim 1 wherein subsequent to said mixing stage, saidstereoregular polyhydrocarbon is heated to a temperature of at least thelst order transition temperature of said stereoregular polyhydrocarbonfor ease of forming into a shaped article.

12. A process of dispersing dye afiinity improving hydrophilic modifierspreferentially into the amorphous regions of poly-4-methyl-1-pentenecomprising:

providing a compacted discontinuous physical mixture of 80 to 99% ofpoly-4-methyl-l-pentene and 1 to 20% of a hydrophilic modifier, andheating said physical mixture to a temperature of less than about 185 C.

mixing said discontinuous physical mixture into a continuous mass at atemperature in the range of 175 C. to 200 C. at a pressure of 2000pounds per square inch.

13. The process of claim 12 wherein said physical mixture is initiallyheated to a temperature of 150 C.

14. The process of claim 12 wherein subsequent to said mixing stage saidmass is heated to a temperature of about 265 C.

15. A process of dispersing dye affinity improving hydrophilic modifierspreferentially into the amorphous regions of polypropylene comprising:

providing a compacted discontinuous physical mixture of to 99% ofpolypropylene and 1 to 20% of a hydrophilic modifier, and

mixing said discontinuous physical mixture into a continuous mass at atemperature in the range of to 170 C. at a pressure of 8000 pounds persquare inch.

16. The process of claim 15 wherein said physical mixture is heated to atemperature of less than 120 C. prior to said mixing stage.

17. The process of claim 15 wherein subsequent to said mixing stage,said mass is heated to a temperature of about 200 C. and formed into ashaped article.

18. A process of dispersing dye affinity improving hydrophilic modifierspreferentially into the amorphous regions of polyethylene comprising:

providing a compacted discontinuous p'hysical mixture of 80 to 99% ofpolyethylene and 1 to 20% of a hydrophilic modifier, and

mixing said discontinuous physical mixture into a continuous mass at atemperature in the range of 100 C. to C. and a pressure of 1000 poundsper square inch.

19. The process of claim 18 wherein said discontinuous physical mixtureis heated to a temperature of 80 C. prior to said mixing stage.

20. The process of claim 18 wherein subsequent to mixing, said mass isheated to C. prior to forming into a shaped article.

References Cited UNITED STATES PATENTS 3,069,220 12/ 1962 Dawson.3,315,014 4/1967 Coover et al. 3,346,521 10/1967 Fairbairn et al.3,315,014 4/ 1967 Coover et al. 3,346,521 10/1967 Fairbairn et al.

WILLIAM H. SHORT, Primary Examiner.

E. A. NIELSEN, Assistant Examiner.

US. Cl. X.R.

